Groove dressing tool



March 21, 1944.

H. H. JOHNSON 2,344,? 80

GROOVE DRESSING TOOL Filed July '22, 1943 accompanying drawing, in which:

Patented Mar. 21, 1944 UNITED STATES PATENT OFFICE GROOVE DRESSING TOOL Herbert H. Johnson, Amory, Miss, assignor of 1t-lI1li;-ty-iive per cent to John T. Crow, Amory,

Application July 22, 1943, Serial No. 495,681

3Claims.

tons of internal combustion engines, side walls of the grooves become fouled with carbon, likewise causing sticking of the rings and consequent pressure loss.

Dressing or cleaning, as the case may be, of

these grooves by machinery usually removes material and results in a widening of the grooves which necessitates replacing the rings with rings of greater widtli to compensate for such widen i1 8;

Endeavor has been made to accomplish the cleaning and dressing by hand, but such cleaning or dressing has usually resulted in widening the face of the groove without correspondingly widening the bottom of the groove and a condition has been set up which could only be corrected by machine operation with the objection able widening of both ring and groove.

The objects of the present invention are:

To make a hand tool which is usable to effect the dressing or cleaning, and which reduces to a minimum the troubles and dangers and costs inherent in the use of the former tools.

The means by which these and other objects are accomplished, and the method of their accomplishment, will readily be understood from the following specification upon reference to the Fig. 1 is a side view of the of my tool.

Fig. 2 is a side elevation of the tool in place Referring now to the drawing in which the various parts are indicated by numerals:

H is a piston, having a circumferential groove 13 therein adapted for the reception of a piston ring. The tool comprises a flat plate-like blade preferred form 7 one edge of which blade is secured a handle I! by which the blade may be operated. The blade is of thickness to loosely fit in the groove ii of the piston with which it is to be used. The length of the blade is preferably greater than the diameter of the piston and the side of the blade opposite the handle is cut away on a reentrant circular arc IQ, of the same radius as the radius of the bottom of the groove It, the depth of the cut away portion being a major portion of the radius of the groove, even approaching a half circle, in order that when the tool is seated in the groove, it will be held against lateral displacement or rocking and parallelism of the sides of the grooves will be maintained. Also the depth of the tool between the handle and the top of the are I! is preferably held to a minimum in order that lateral rocking thrust may be reduced as much as possible. Minor indentations 2| are preferably formed in opposite faces of the tool, those on one side only being shown, along the curve of the arc, the indentations preferably not extending to the arc and being conveniently stamped into the plate as by the use of a tool having the configuration of the letter H.

,In use, a tool of proper thickness and are radius is thinly coated. on its opposite faces, but not along its arcuate face with a grinding compound in paste form, or with an oil carrier on which finely powdered carborundum, emery or the like is dusted, the indentations 2i filling with and retaining the compound. The tool is seated in the groove and shifted with a circulatory movement around the piston until projections and/or accretions are removed, leaving the groove of original shape and form to receive the ring. In such movement the seating depth of the tool eflectually prevents any appreciable or measur- I! of metal, preferably hardened steel, along as able flaring of the groove, the length of the are also substantially, compelling uniform dressing action and preventing local widening except through intention or grossest carelessness.

After dressing, .the groove is thoroughly washed out to remove all traces of grinding material.

I claim:

1. A tool for dressing a circular groove as being a major portion of the radius oi the groove, said plate being scored concentrically along said are as to receive a grinding compound.

2. A tool for dressing a circular groove as of a piston, comprising a flat plate having a thickness loosely conforming to the width of said radius of the bottom 01 said groove and to a depth approaching said radius, and said handle being spaced less than said radius from said arc.

3. A tool for dressing a circular groove as o! a piston; comprising-a flat metal plate having a thickness loosely conforming to the width of said groove and a length at least equal to the diameter 01 said piston, said plate having one of its side edges cut away along a reentrant circular arc conforming to the radius or the bottom of said groove to a depth approaching said radius, said plate being scored concentrically along said are 10 as to receive a grinding compound.

HERBERT H. JOHNSON. 

